The term "Affordance" refers to the opportunities for action offered by a specific object or environment . For example, the handle on a tea pot offers the affordance of holding and pouring.
Affordance Theory as defined by J.J.Gibson, states that one perceives the world not only in terms of object shapes and spacial relations but also as object action possibilities (affordances) - ones perception of an object implies the action associated with it.Gibson states that affordances exist naturally in the environment and are instantly perceived by the viewer requiring no sensory processing. Based on Gestalt theories, affordance theory has a large impact and various implications for design, human-computer interaction, visualization, human factors engineering and ergonomics, which is in part concerned with the perceived affordances of an object design.
Jon Von Uexküll (1920) identified the “functional colouring” of objects in relation to how one might perceive the world in terms of its action possibilities Similarly Koffka(1935) , described the perceived meaning of objects by effectively describing perceived affordances. These initial constructs were limited in that they described affordances as requiring perception and were dependent on agent and an object. Perceptual psychologist James J. Gibson introduced the term affordance in“The Theory of Affordances” (J. Gibson 1977). In his book The Ecological Approach to Visual Perception (J. Gibson 1979), Gibson defined an affordance as an interdependence between the agent and the context or environment.
James Jerome Gibson
American cognitive psychologist, James Jerome Gibson (1904–1979), was considered one of the most important psychologists in the field of visual perception in the 20th century.
Born in McConnelsville, Ohio, J.J.Gibson received his Ph.D. in Psychology from Princeton University in 1928 and joined the faculty of Smith College where over the following 15 years, he taught courses in social and experimental psychology while publishing numerous research papers in collaboration with his students. In 1932, he married Eleanor J.Gibson (nee Jack), who also became a prominent psychologist. During World War II (1942-46) Gibson served in the Army Air Forces, where he conducted research on visual aircraft identification and training films. After the war Gibson returned to Smith College until his move to Cornell University in 1949. Gibson retired from Cornell University, in Ithaca New York in 1972.
In his classic work The Perception of the Visual World (1950), Gibson rejected the popular theory of behaviorism for a perspective based on his own experimental work. Gibson hypothesized that animals" 'sampled' information from the 'ambient' outside world" and from this developed his "ecological approach" to the study of visual perception relating to how humans perceive the immediate environment without the use of cognitive processes or sense data. Perceiving a flower for example, does not require a mental image construction sourced from stimuli entering the retina then designing the image. Alternately, one sees the direct properties of the flower.
William Gaver (1991) separated affordances into three categories: Perceptible, Hidden and False.
- A perceptible affordance exists when information on the action is apparent to the user. The user perceives and then acts on the existing affordance i.e.; a push on/off switch for a radio.
- A false affordance refers to an apparent affordance or "action possibility" that does not offer any real function, meaning that one perceives a possibility for action but none exists.  ie; a placebo.- the user falsely perceives some action from the placebo medication but in fact none exists.
- A hidden affordance is an action that is possible, is not visible but may be inferred.ie; A cane is perceived as a walking aid, but a hidden affordance could be using it as a weapon.
Therefore, when an affordance is perceptible a direct link between perception and action is identified. When affordances are false or hidden, misunderstanding and mistakes may happen.
Real and Perceived Affordances
According to Norman (1999), Real affordances relate to the physical properties of an object or environment that permits a user to perform an action even if the user does or does not perceive the affordance.Norman posits that perceived affordances are different from Real affordances and that perceived affordances don't have to support real ones. Further, he argues that a real affordance are still considered "real" even if they are hidden.
Gibson on the other hand argues that an affordance may refer to " “whatever it is about the environment that contributes to the kind of interaction that occurs” , whether the user recognizes the affordance or the object exhibits the affordance, it is considered an affordance as long as the user is capable of performing the action through interaction. Therefore, the affordance is based on the users ability along with “Additional conditions that include aspects of the activity of an agent in the situation, having to do with motivation and perception.”  And so Gibson's process of affordance can be viewed as :
The study of affordances advances research in the domains of applied and behavioral science domains.Within the realm of behavioural sciences affordances shed a light on learning and imitation in perceptual science in relation to direct perceptual research. Based on Gibsons work in direct perception, a new perceptual theory emerged which does not support the idea of passive absorption of the context or environment, rather, ones perception guides an action in a direct fashion, creating intent of action.
Researchers such as Eleanor Gibson have built on the base definition of affordances offered by her husband J.J.Gibson. Her work on the process of learning through affordances brought her to a new approach she refers to as differentiation  Eleanor Gibson posits that learning happens by a process that creates a distinction between an existing affordance and another new affordance, thus, creating a splitting of actions into many other specific actions.  creating a thought process like that of a chain reaction.
In the world of Applied sciences affordances influence human-computer interaction, human stimulation and robotics. In these studies, the human-computer interaction relies on affordances to direct the design principles of interface actions that allow the item to have an obvious function based on its appearance.. The study of robotics uses affordance theory and learning for situational uses such as robot appendages-arms and independent vehicle design. Researchers Silverman et al. (2006),  simulated humans who interact with their environment through clues noted in environmental affordances. This paradigm identifies how robots and the environment are designed independent of each other yet the affordances dictate or define the activities between them.
Affordances also influence the systems research conducted by John Holland (1996) . In his writings "Hidden Order", John Holland's research on complex adaptive systems presents an adaptive mechanism based on the affordance theory schema.
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Works by J.J.Gibson
"Adaptation, After-Effect and Contrast in the Perception of Curved Lines.” Journal of Experimental Psychology 16 (1933): 1–31."
Motion Picture Testing and Research. Aviation Psychology Research Reports, no. 7. Washington, DC, 1948."
The Perception of the Visual World. Boston: Houghton-Mifflin, 1950.
With Paul Olum and Frank Rosenblatt. “Parallax and Perspective during Airplane Landing.” American Journal of Psychology 68 (1955): 372–385.
With Eleanor J. Gibson. “Perceptual Learning: Differentiation or Enrichment?” Psychological Review 62 (1955): 32–41.
“Visually Controlled Locomotion and Visual Orientation in Animals and Men.” British Journal of Psychology 49 (1958): 182–194.
“The Concept of the Stimulus in Psychology.” American Psychologist 16 (1960): 694–703.
With William Schiff and James Caviness. “Persistent Fear Responses in Rhesus Monkeys to the Optical Stimulus of ‘Looming.’” Science 136 (1962): 982–983.
The Senses Considered as Perceptual Systems. Boston: Houghton-Mifflin, 1966.
“James J. Gibson.” In A History of Psychology in Autobiography, vol. 5, edited by E. G. Boring and G. Lindzey. New York: Appleton-Century-Crofts, 1967.
“New Reasons for Realism.” Synthese 17 (1967): 162–172.
With George Kaplan, Horace Reynolds, and Kirk Wheeler. “The Change from Visible to Invisible: A Study of Optical Transitions.” Perception & Psychophysics 5 (1969): 113–116.
“The Information Available in Pictures.” Leonardo 4 (1971): 27–35.
The Ecological Approach to Visual Perception. Boston: Houghton-Mifflin, 1979.
Reasons for Realism: Selected Essays of James J. Gibson. Edited by E. S. Reed and R. Jones. Hillsdale, NJ: Lawrence Erlbaum Associates, 1982. A full listing of Gibson’s works.
- Affordance theory of learning. Retrieved February 19, 2014 from http://educationatlas.com/affordance-theory-of-learning.html#ixzz2u3u5bQZg]
- [ Uexküll, Jakob von (1980 [1920 etc.]), Kompositionslehre der Natur, edited by Thure von Uexküll, Frankfurt am Main.]
- [Koffka, K (1935). Principles of Gestalt Psychology. London: Lund Humphries,.]
- [Nye, B. D. & Silverman, B. G. (2012). Affordance. In N. M. Seel (Ed.),Encyclopedia of the Sciences of Learning (pp. 179-183). New York, NY: Springer. doi: 10.1007/978-1-4419-1428-6_369 Link text]
- [ James J. Gibson. (2014). Encyclopædia Britannica. Retrieved from http://www.britannica.com/EBchecked/topic/233285/James-J-Gibson]
- Gaver, W. (1991). Technology affordances. In Proceedings of the CHI 1991, ACM Press: New York, 79 – 84.]
- [Donald A. Norman (1999). Affordance, Conventions and Design. Interactions 6(3):38-43, May 1999, ACM Press.]
- [Real, Perceived, and Hidden Affordances. (August 29, 2013) Retrieved from http://mahaalfreih.com/uncategorized/hello-world/]
- [Gibson, Eleanor J. and Pick, Anne D. (2000). An Ecological Approach to Perceptual Learning and Development. Oxford University Press, USA.]
- [Norman, Donald A. (1988). The Design of Everyday Things. New York: Doubleday]
- [Silverman, B. G., Johns, M., Cornwell, J. B., & O'Brien, K. (2006). Human behavior models for agents in simulators and games: Part I: Enabling science with PMFServ. Presence: Teleoperators & Virtual Environments,15 (2), 139-162.]
- [Holland, J. (1996) Hidden Order: How Adaptation Builds Complexity. Addison-Wesley]